M1028 plug and air tank in bed.

[Mattguy]

Is this plug missing something? The switch in my hand leads back to an air tank in bed. But no compressor. Looks like it was filled through a Schrader on top. Anyone see this before? Thanks for any help.

 

[Keith_J]

Looks like the holder for the glow plug card. The air tank is something the prior owner added.

 

[Mattguy]

Looks like the holder for the glow plug card. The air tank is something the prior owner added.

I got the truck direct from the USMC. They added the tank. The rectangle plug is for a glow plug controller? I've searched all tm's and can't find this plug on a wiring harness for dash.

 

[NDT]

Usmc must have had an air horn added from a 5 ton etc.

 

[Mattguy]

Found this relay added in. Would that be because the glow plug controller is missing. They did add a huge siren.

 

[Mattguy]

Usmc must have had an air horn added from a 5 ton etc.

You are correct! Followed air line to two tone horn in grille.

 

[Keith_J]

Wiring diagrams are function specific, glow plug controller card is found in the -34 TM appendix E-7. Thanks for making provenance clear. How many crayons did you find under the seat? Ammonia works well to clean the spittle from the windows

 

[M1009_SPAIN]

Found this relay added in. Would that be because the glow plug controller is missing. They did add a huge siren.

the empty plug is for the glow plug controller board.
You have the spark plug relay in the firewall to the right of the one that the horn was connected to, it is identical

 

[Mattguy]

the empty plug is for the glow plug controller board.
You have the spark plug relay in the firewall to the right of the one that the horn was connected to, it is identical

So they put a relay for the glow plug on firewall? I do have a switch on the dashboard that I thought was for manual glow plug operation.

 

[Mullaney]

So they put a relay for the glow plug on firewall? I do have a switch on the dashboard that I thought was for manual glow plug operation.

.
The dash switch is where somebody bypassed the factory way of turning on the glow plugs

 

[M1009_SPAIN]

.
The dash switch is where somebody bypassed the factory way of turning on the glow plugs

Exactly, it was easier/cheaper for them to make a manual drive, than to install. a new glow plug controller board.

It is a very common process, do not be alarmed